All about “Boeing Apache” : One of the future attack helicopter of Indian AirForce

The Boeing AH-64 Apache is an American four-blade, twin-turboshaft attack helicopter with a tailwheel-type landing gear arrangement and a tandem cockpit for a two-man crew. It features a nose-mounted sensor suite for target acquisition and night vision systems. It is armed with a 30 mm (1.18 in) M230 chain gun carried between the main landing gear, under the aircraft’s forward fuselage. It has four hardpoints mounted on stub-wing pylons, typically carrying a mixture of AGM-114 Hellfire missiles and Hydra 70 rocket pods. The AH-64 has a large amount of systems redundancy to improve combat survivability.

The U.S. Army is the primary operator of the AH-64; it has also become the primary attack helicopter of multiple nations, including Greece, Japan, Israel, the Netherlands, Singapore, and the United Arab Emirates; as well as being produced under license in the United Kingdom as the AgustaWestland Apache. American AH-64s have served in conflicts in Panama, the Persian Gulf, Kosovo, Afghanistan, and Iraq. Israel used the Apache in its military conflicts in Lebanon and the Gaza Strip; British and Dutch Apaches have seen deployments in wars in Afghanistan and Iraq.

Design :

Overview
The AH-64 Apache has a four-blade main rotor and a four-blade tail rotor. The crew sits in tandem, with the pilot sitting behind and above the co-pilot/gunner. Both crew members are capable of flying the aircraft and performing methods of weapon engagements independently. The AH-64 is powered by two General Electric T700 turboshaft engines with high-mounted exhausts on either side of the fuselage. Various models of engines have been used on the Apache; those in British service use engines from Rolls-Royce. In 2004, General Electric Aviation began producing more powerful T700-GE-701D engines, rated at 2,000 shp (1,500 kW) for AH-64Ds.

Avionics and targeting :
One of the revolutionary features of the Apache was its helmet mounted display, the Integrated Helmet and Display Sighting System (IHADSS); among its capabilities, either the pilot or gunner can slave the helicopter’s 30 mm automatic M230 Chain Gun to their helmet, making the gun track head movements to point where they look. The M230E1 can be alternatively fixed to a locked forward firing position, or controlled via the Target Acquisition and Designation System (TADS). On more modern AH-64s, the TADS/PNVS has been replaced by Lockheed Martin’s Arrowhead (MTADS) targeting system.

U.S. Army engagement training is performed under the Aerial Weapons Scoring System Integration with Longbow Apache Tactical Engagement Simulation System (AWSS-LBA TESS), using live 30 mm and rocket ammunition as well as simulated Hellfire missiles. The Smart Onboard Data Interface Module (SMODIM) transmits Apache data to an AWSS ground station for gunnery evaluation. The AH-64’s standard of performance for aerial gunnery is to achieve at least 1 hit for every 30 shots fired at a wheeled vehicle at a range of 800–1,200 m (870–1,310 yd).

The AH-64 was designed to perform in front-line environments, and to operate at night or day and during adverse weather conditions. Various sensors and onboard avionics allows the Apache to perform in these conditions; such systems include the Target Acquisition and Designation System, Pilot Night Vision System (TADS/PNVS), passive infrared countermeasures, GPS, and the IHADSS. Longbow-equipped Apaches can locate up to 256 targets simultaneously within 50 km (31 mi). In August 2012, 24 U.S. Army AH-64Ds were equipped with the Ground Fire Acquisition System (GFAS), which detects and targets ground-based weapons fire sources in all-light conditions and with a 120° Visual field. The GFAS consists of two sensor pods working with the AH-64’s other sensors, and a thermographic camera that precisely locates muzzle flashes.
In 2014, it was announced that new targeting and surveillance sensors were under development to provide high-resolution color imagery to crews, replacing older low definition black-and-white imaging systems. Lockheed received the first contract in January 2016, upgrading the Arrowhead turret to provide higher-resolution color imaging with longer ranges and a wider field of view. In 2014, the U.S. Army was adapting its Apaches for increased maritime performance as part of the Pentagon’s rebalance to the Pacific. Additional avionics and sensor improvements includes an extended-range radar capable of detecting small ships in littoral environments, software adaptions to handle maritime targets, and adding Link 16 data-links for better communications with friendly assets

Armaments and configurations :
The AH-64 is adaptable to numerous different roles within its context as Close Combat Attack (CCA). In addition to the 30 mm M230E1 Chain Gun, the Apache carries a range of external stores and weapons on its stub-wing pylons, typically a mixture of AGM-114 Hellfire anti-tank missiles, and Hydra 70 general-purpose unguided 70 mm (2.756 in) rockets. One 18-aircraft Apache battalion equipped with Hellfire missiles is capable of destroying 288 tanks. Since 2005, the Hellfire missile is sometimes outfitted with a thermobaric warhead; designated AGM-114N, it is intended for use against ground forces and urban warfare operations. The use of thermobaric “enhanced blast” weapons, such as the AGM-114N, has been a point of controversy. In October 2015, the U.S. Army ordered its first batch of Advanced Precision Kill Weapon System (APKWS) guided 70 mm rockets for the Apache.

Starting in the 1980s, the Stinger and AIM-9 Sidewinder air-to-air missiles and the AGM-122 Sidearm anti-radiation missile were evaluated for use upon the AH-64. The Stinger was initially selected; the U.S. Army was also considering the Starstreak air-to-air missile. External fuel tanks can also be carried on the stub wings to increase range and mission time. The stub-wing pylons have mounting points for maintenance access; these mountings can be used to secure externally personnel for emergency transportation. Stinger missiles are often used on non-U.S. Apaches, as foreign forces do not have as many air superiority aircraft to control the skies. The AH-64E initially lacked the ability to use the Stinger to make room for self-defense equipment, but the capability was re-added following a South Korean demand.

The AH-64E Apache has the ability to control unmanned aerial vehicles (UAVs), used by the U.S. Army to perform aerial scouting missions previously performed by the OH-58 Kiowa. Apaches can request to take control of an RQ-7 Shadow or MQ-1C Grey Eagle from ground control stations to safely scout via datalink communications. There are four levels of UAV interoperability (LOI): LOI 1 indirectly receives payload data; LOI 2 receives payload data through direct communication; LOI 3 deploys the UAV’s armaments; and LOI 4 takes over flight control. UAVs can search for enemies and, if equipped with a laser designator, target them for the Apache or other friendly aircraft.

Boeing has suggested that the AH-64 could be fitted with a directed energy weapon. The company has developed a small laser weapon, initially designed to engage small UAVs, that uses a high-resolution telescope to direct a 2-10 kW beam with the diameter of a penny out to a range of 5.4 nmi (10.0 km; 6.2 mi). On the Apache, the laser could be used to destroy enemy communications or radio equipment.

On 14 July 2016 it was reported that the AH-64 had successfully completed testing of the MBDA Brimstone anti-armor missile.

Variants :

AH-64A
The AH-64A is the original production attack helicopter. The crew sit in tandem in an armored compartment. It is powered by two GE T700 turboshaft engines. The A-model was equipped with the −701 engine version until 1990 when the engines were switched to the more powerful −701C version.

U.S. Army AH-64As are being converted to AH-64Ds. The service’s last AH-64A was taken out of service in July 2012 before conversion at Boeing’s facility in Mesa, Arizona. On 25 September 2012, Boeing received a $136.8M contract to remanufacture the last 16 AH-64As into the AH-64D Block II version and this was forecast to be completed by December 2013

AH-64B :
In 1991, after Operation Desert Storm, the AH-64B was a proposed upgrade to 254 AH-64As. The upgrade would have included new rotor blades, a Global Positioning System (GPS), improved navigation systems and new radios. Congress approved $82M to begin the Apache B upgrade. The B program was canceled in 1992. The radio, navigation, and GPS modifications, were later installed on most A-model Apaches through other upgrades.

AH-64C :
Additional funding from Congress in late 1991 resulted in a program to upgrade AH-64As to an AH-64B+ version. More funding changed the plan to upgrade to AH-64C. The C upgrade would include all changes to be included in the Longbow except for mast-mounted radar and newer −700C engine versions. However, the C designation was dropped after 1993. With AH-64As receiving the newer engine from 1990, the only difference between the C model and the radar-equipped D model was the radar, which could be moved from one aircraft to another; thus the decision was made to simply designate both versions “AH-64D”.

AH-64D :
The AH-64D Apache Longbow is equipped with a glass cockpit and advanced sensors, the most noticeable of which being the AN/APG-78 Longbow millimeter-wave fire-control radar (FCR) target acquisition system and the Radar Frequency Interferometer (RFI), housed in a dome located above the main rotor. The radome’s raised position enables target detection while the helicopter is behind obstacles (e.g. terrain, trees or buildings). The AN/APG-78 is capable of simultaneously tracking up to 128 targets and engaging up to 16 at once, an attack can be initiated within 30 seconds. A radio modem integrated with the sensor suite allows data to be shared with ground units and other Apaches; allowing them to fire on targets detected by a single helicopter.

The aircraft is powered by a pair of uprated T700-GE-701C engines. The forward fuselage was expanded to accommodate new systems to improve survivability, navigation, and ‘tactical internet’ communications capabilities. In February 2003, the first Block II Apache was delivered to the U.S. Army, featuring digital communications upgrades. The Japanese Apache AH-64DJP variant is based on the AH-64D; it can be equipped with the AIM-92 Stinger air-to-air missiles for self-defense.

AH-64E :
Formerly known as AH-64D Block III, in 2012, it was redesignated as AH-64E Guardian to represent its increased capabilities.The AH-64E features improved digital connectivity, the Joint Tactical Information Distribution System, more powerful T700-GE-701D engines with upgraded face gear transmission to accommodate more power, capability to control unmanned aerial vehicle (UAVs), full IFR capability, and improved landing gear. New composite rotor blades, which successfully completed testing in 2004, increase cruise speed, climb rate, and payload capacity. Deliveries began in November 2011. Full-rate production was approved on 24 October 2012, with 634 AH-64Ds to be upgraded to AH-64E standard and production of 56 new-build AH-64Es to start in 2019/20. Changes in production lots 4 through 6 shall include a cognitive decision aiding system and new self-diagnostic abilities. The updated Longbow radar has an oversea capacity, potentially enabling naval strikes; an AESA radar is under consideration. The E model is to be fit for maritime operations. The Army has expressed a desire to add extended-range fuel tanks to the AH-64E to further increase range and endurance. AH-64Es are to have the L-3 Communications MUM-TX datalink installed in place of two previous counterparts, communicating on C, D, L, and Ku frequency bands to transmit and receive data and video with all Army UAVs. Lots 5 and 6 will be equipped with Link 16 data-links.

AH-64F :
In 2014, Boeing conceptualized an Apache upgrade prior to the introduction of the U.S. Army’s anticipated attack version of the Future Vertical Lift aircraft, forecast to replace the Apache by 2040. The conceptual AH-64F would have greater speed via a new 3,000 shp turboshaft engine from the improved turbine engine program, retractable landing gear, stub wings to offload lift from the main rotor during cruise, and a tail rotor that can articulate 90 degrees to provide forward thrust. In October 2016, the Army revealed they would not pursue another Apache upgrade to focus on funding the FVL; the Army will continue buying the Apache through the 2020s until Boeing’s production line ends in 2026, then FVL is slated to come online in 2030

Sea Apache :
During the 1980s naval versions of the AH-64A for the United States Marine Corps and Navy were examined. Multiple concepts were studied with altered landing gear arrangements, improved avionics and weapons. The USMC was very interested and conducted a two-week evaluation of the Apache in September 1981, including shipboard operation tests.
Funding for a naval version was not provided; the Marine Corps continued to use the AH-1. The Canadian Forces Maritime Command also examined a naval Apache. In 2004, British Army AgustaWestland Apaches were deployed upon the Royal Navy’s HMS Ocean, a Landing Platform Helicopter, for suitability testing; there was U.S. interest in the trials.
During the 2011 military intervention in Libya, the British Army extensively used Apaches from HMS Ocean. In 2013, U.S. 36th Combat Aviation Brigade AH-64Ds were tested on a variety of U.S. Navy ships.

Export Apaches :
Several models have been derived from both AH-64A and AH-64D for export. The British-built AgustaWestland Apache (assembled from kits purchased from Boeing) is based on the AH-64D Block I with several different systems, including more powerful engines, folding rotor blades, and other modifications for operation from Royal Navy vessels.

Block modification :
While a major change in design or role will cause the type designator suffix to change, for example from AH-64D to AH-64E, the helicopters are also subject to block modification. Block modification is the combining of equipment changes into blocks of modification work orders, the modifications in the block (sometimes called a block package) are all done to the helicopter at the same time.

India :
In 2008, the Indian Air Force (IAF) released a tender for 22 attack helicopters; there were six contending submissions—Sikorsky’s UH-60 Black Hawk, the AH-64D, Bell’s AH-1 Super Cobra, Eurocopter’s Tiger, Mil’s Mi-28 and AgustaWestland’s A129 Mangusta. In October 2008, Boeing and Bell withdrew. In 2009, the competition was restarted. In December 2010, India requested the possible sale of 22 Apaches and associated equipment. On 5 October 2012, IAF Chief NAK Browne confirmed the Apache’s selection. The IAF sought control of the 22 proposed Apaches for air combat missions, while the Army Aviation Corps argued that they would be better used in army operations. In April 2013, the Indian Ministry of Defence (MoD) decided that the IAF would receive the 22 AH-64s. In May 2013, the Indian Army requested 11 AH-64Es; and has a requirement for 39 Apaches. The Indian Ministry of Defence approved the procurement in August 2014, as did India’s Cabinet Committee on Security (CCS) in September 2015. On 28 September 2015, a contract was formally signed; the first helicopter is expected to be delivered to India in the next three to four years

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